I would like to use cvtColor to convert a cv::Mat from RGBA to NV12. However, according to the doc it is only possible from YUV to NV12. I don’t know what color space conversion code to use.
The format I need as an output is YUV420 (NV12).
Thank you in advance.
Apparently you may need a couple of steps for the conversion: RGBA to BGR, BGR to YUV, and finally YUV to NV12…
I tried doing that as so :
opencvMatrix = cv::Mat(*(params.height), *(params.width), CV_8UC4, (char*)(pointer), *(params.pitch));
cv::cvtColor(opencvMatrix, opencvMatrix, cv::COLOR_RGBA2RGB);
cv::cvtColor(opencvMatrix, opencvMatrix, cv::COLOR_RGB2YUV);
cv::cvtColor(opencvMatrix, opencvMatrix, cv::COLOR_YUV2RGB_NV12);
However I get the following error :
OpenCV Error: Assertion failed (sz.width % 2 == 0 && sz.height % 3 == 0 && depth == CV_8U) in cvtColor, file /usr/src/debug/opencv/3.2.0-r0/git/modules/imgproc/src/color.cpp, line 9865 terminate called after throwing an instance of 'cv::Exception' what(): /usr/src/debug/opencv/3.2.0-r0/git/modules/imgproc/src/color.cpp:9865: error: (-215) sz.width % 2 == 0 && sz.height % 3 == 0 && depth == CV_8U in function cvtColor
If I simply use the first conversion it works but I need the output to be in NV12 format.
for which of the three calls do you get that?
why do you use in-place operation? that is not possible for the last operation. give it a separate result matrix.
why do you seem to dereference
params.height? it’s a number, not a pointer, right?
As far as I can tell that is from YUV(NV12) to RGB. It doesn’t look like there is a function to convert to NV12, what do you need NV12 for?